Using formal methods to support testing

Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing

Quantifying and Predicting the Influence of Execution Platform on Software Component Performance

The performance of software components depends on several factors, including the execution platform on which the software components run. To simplify cross-platform performance prediction in relocation and sizing scenarios, a novel approach is introduced in this thesis which separates the application performance profile from the platform performance profile. The approach is evaluated using transparent instrumentation of Java applications and with automated benchmarks for Java Virtual Machines

Towards quality programming in the automated testing of distributed applications

PhD ThesisSoftware testing is a very time-consuming and tedious activity and accounts for over 25% of the cost of software development. In addition to its high cost, manual testing is unpopular and often inconsistently executed. Software Testing Environments (STEs) overcome the deficiencies of manual testing through automating the test process and integrating testing tools to support a wide range of test capabilities. Most prior work on testing is in single-thread applications. This thesis is a contribution to testing of distributed applications, which has not been well explored. To address two crucial issues in testing, when to stop testing and how good the software is after testing, a statistics-based integrated test environment which is an extension of the testing concept in Quality Programming for distributed applications is presented. It provides automatic support for test execution by the Test Driver, test development by the SMAD Tree Editor and the Test Data Generator, test failure analysis by the Test Results Validator and the Test Paths Tracer, test measurement by the Quality Analyst, test management by the Test Manager and test planning by the Modeller. These tools are integrated around a public, shared data model describing the data entities and relationships which are manipulable by these tools. It enables early entry of the test process into the life cycle due to the definition of the quality planning and message-flow routings in the modelling. After well-prepared modelling and requirements specification are undertaken, the test process and the software design and implementation can proceed concurrently. A simple banking application written using Java Remote Method Invocation (RMI) and Java DataBase Connectivity (JDBC) shows the testing process of fitting it into the integrated test environment. The concept of the automated test execution through mobile agents across multiple platforms is also illustrated on this 3-tier client/server application.The National Science Council, Taiwan: The Ministry of National Defense, Taiwan

Variations in low-grade wood modification and stress lamination

Sitka spruce (Picea sitchensis) trees in UK forests are expected to yield nearly 30% more softwood than current levels in the coming decades. These are relatively fast-growing trees, yielding low-grade wood that is incompatible with standards for glue-based lamination. Alongside this forecasted increase, there is a major worldwide shift towards building taller and faster with massive laminated and engineered wood products, mainly as substitutes for steel and concrete. For making the best use of the expected increase in UK softwood and also to expand the scope of tall wood construction, alternative ways of working with low-grade wood are needed, along with developing new variations of existing techniques in processing and construction. This thesis examines two strategies: wood modification by impregnation and stress lamination. The former involves treating wood under pressure in a liquid solution. Once impregnated, the liquid is then solidified in-situ, grafting onto the wood to enhance its properties through direct molecular interactions in the cell wall. While wood treatments are usually done to increase durability, literature and preliminary small-scale testing suggest that impregnation can also lead to increases in stiffness and strength. Compared to wood modification, stress lamination is a relatively simple yet effective technique, and is useful for laminating wood without glue. Although widely used in timber bridges, stress lamination has found little to no application in buildings, primarily due to concerns regarding losses in prestress levels from creep and the moisture-related movement and shrinkage of wood. Scale models and testing emphasise the technique’s potential for both standard and bespoke structural elements for buildings. Full-scale detailing, construction, and testing of straight columns further establishes structural performance and feasibility. Test results from shearing five full-scale stress-laminated connections show performance beyond that of conventional mechanical fasteners. Twenty-five columns were also tested at full-scale, showing comparable buckling performance to Eurocode estimates for solid timber. Examples from literature and a new detail with overdried hardwood plates, tested during a six-month period, demonstrate that prestress losses can be mitigated to ensure long-term reliability in buildings. The full-scale testing performed in this thesis therefore highlights the usefulness, performance, and reliability of stress lamination with low-grade wood for multi-storey construction.UK Engineering and Physical Sciences Research Council (EPSRC) Cambridge Commonwealth Trust Ramboll Foundation Natural Sciences and Engineering Research Council of Canada (NSERC